Flying after a knee replacement
Same clot risk as a hip replacement, plus a practical problem nobody warns you about: a stiff new knee does not bend well into an economy seat.
The short answer. Up to 12 weeks for a long flight; often sooner for a short one. As with hip replacement, the restriction is about clot risk rather than the joint. NHS surgical travel guidance advises caution for prolonged flights, particularly those over four hours.
The clot risk
Knee replacement carries a similar elevated risk of venous thromboembolism to hip replacement. Clotting tendency stays raised for weeks, the leg is swollen, and the calf muscle pump is impaired by pain and reduced movement. Several hours immobile in a seat adds to that, which is why guidance for flights over four hours is conservative.
The practical problem: you cannot bend it
This gets underestimated. In the early weeks after a knee replacement, knee flexion is limited and often painful. Standard economy seat pitch requires roughly 90 degrees of knee bend, sustained for hours. If you cannot comfortably achieve that yet, the flight will be genuinely miserable regardless of clot risk — and being unable to straighten the leg periodically is itself bad for swelling.
A bulkhead seat, an extra-legroom row or an aisle seat where you can extend the leg makes a substantial difference. Arrange it when booking.
If you are flying
- Ask your surgeon about extending thromboprophylaxis around the flight
- Book a seat you can actually straighten your leg in
- Walk every hour or two; do ankle pumps constantly while seated
- Compression stockings if advised, properly fitted
- Airport assistance — do not underestimate terminal distances on crutches
- Keep the leg elevated where you can, including in the lounge
When not to fly
Do not fly and get assessed the same day if you have new or increasing calf pain, swelling, warmth or redness, sudden breathlessness or chest pain, a wound that is red, hot or discharging, or a fever. Do not travel through a planned post-operative review without checking with your team.
Common questions
How soon can you fly after a knee replacement?
For flights over four hours, up to around 12 weeks is commonly advised because of clot risk. Short flights are often permitted earlier. Your surgeon should make the call for your specific recovery and trip.
Can I get a seat with more legroom?
Yes, and it is worth arranging when you book rather than hoping at the gate. Bulkhead and extra-legroom rows let you keep the leg straighter, which helps both comfort and swelling.
Will the implant set off airport scanners?
Occasionally. Modern implants often do not trigger walk-through detectors, but if yours does, expect a pat-down. Carrying an implant card does no harm though it is not treated as proof.
Should I wear compression stockings on the flight?
If your surgical team has advised them, yes, and make sure they fit properly. Graduated compression is what matters — ordinary tight socks are not the same thing.
What if I have already booked a holiday?
Speak to your surgeon as early as you can. If travel is not advisable, a not fit to fly certificate is what your insurer will need — and notify them promptly rather than close to departure.
Related
Sources. The airline and clinical facts on this page were checked against these primary sources on 24 August 2026. Airline policies change without notice — always confirm with your airline before you book or travel.
Need a fit to fly certificate after surgery?
If your airline or insurer has asked for medical confirmation that you are fit to travel, a GMC-registered UK GP can review your case and issue the letter.
Get startedReviewed by a GMC-registered GP. Full refund if a certificate cannot be issued on clinical grounds.